Managing premenstrual symptoms at the most fundamental level necessitates careful consideration of female reproductive biology. Inhibiting ovulation using hormonal agents is a reasonable approach for reducing premenstrual symptoms, but the benefits of agents such as gonadotropin-releasing hormone agonists and the synthetic androgen danazol are largely offset by their adverse effects and costs. Combination oral contraceptives provide an alternative that is widely accepted by women experiencing premenstrual symptoms and by their physicians; and newer formulations with lower levels of estrogen and progestin, administered using a monthly regimen with a shortened pill-free interval, appear promising for alleviating patient distress from severe premenstrual symptoms.
(Am J Manag Care. 2005;11:S492-S497)
The biology of menstrually related symptoms involves either direct or indirect interaction of the ovarian cycle with key hormones, neurotransmitters, or other substances.1 A menstruating woman may experience symptoms in the late luteal phase of her ovulatory cycle throughout her childbearing years. To provide relief for women who suffer moderately or severely from any combination of these symptoms, it would seem prudent to seek a solution that works in tandem with female physiology to restore health-related quality of life and an overall sense of well-being with the fewest possible adverse effects.
Symptoms related to the menstrual cycle may be limited to mild discomfort or extend to premenstrual syndrome (PMS) or to premenstrual dysphoric disorder (PMDD), which would include severe emotional and somatic impairment. Only limited research on alleviation of menstrual symptoms has been conducted to date on women meeting the diagnostic criteria published by the American College of Obstetricians and Gynecologists2 for PMS and by the American Psychiatric Association for PMDD.3 However, research on premenstrual symptoms in general may provide strategies for effective treatments for PMS and PMDD.
Premenstrual symptoms occur almost exclusively in ovulatory cycles; therefore, inhibiting ovulation could be expected to reduce or eliminate these symptoms. Gonadotropin-releasing hormone (GnRH) agonists can be used to suppress ovulation and effectively alleviate premenstrual symptoms. However, because using GnRH agonists leads to a hypoestrogenic state, "add-back" hormone therapy with estrogen or estrogen/progesterone is necessary to prevent menopausal symptoms such as hot flashes and to minimize bone loss that could occur with steady use.4 These agents are costly and are not recommended for long-term use.
Another hormonally mediated possibility, the synthetic androgen danazol, suppresses ovulation as well, but its use is limited by an array of adverse effects. These include weight gain; decreased high-density lipoprotein cholesterol, which may increase the risk of cardiovascular disease; and, at higher doses, the possibility of greater facial hair growth and severity of acne.4 Like GnRH agonists, danazol is not recommended for long-term use.
Combination oral contraceptives (OCs), which contain estrogen and one of several progestins, are commonly prescribed hormonal agents providing a variety of noncontraceptive health benefits, aside from preventing pregnancy. Combination OCs have been widely used to treat physical premenstrual symptoms. Women and their physicians have a high level of comfort with their use, and OC users benefit from their relatively low cost and positive effects on the menstrual cycle.
Few controlled trials have evaluated OCs for their effects on premenstrual symptoms, and past studies demonstrated little difference in the experience of OC users and nonusers in this regard.5,6 Evidence for OC effects on premenstrual symptoms is weakened, according to a recent review of the medical literature, by the fact that early studies were conducted using OCs with the high estrogen doses commonly employed at that time. The reduced estrogen doses in current OC formulations may result in a decreased degree of ovarian inhibition compared with that afforded by older OCs, especially during the pill-free interval.7
In the female reproductive system, the degree of follicular activity during OC use is dependent on the type and dose of steroids used, the type of regimen, user adherence, and individual metabolic responsiveness to the OC prescribed.7 Early OC formulations with high doses of estrogen and progestin caused many adverse effects, including nausea, breast tenderness, and fluid retention. These symptoms resulted in a high rate of premature discontinuation of use, and therefore hormone doses in combined OCs have been reduced. OCs inhibit follicular development, and high-dose OCs maintain steroid levels sufficient to suppress ovarian function during the pill-free interval; with low-dose OCs, however, effective serum levels of ethinyl estradiol (EE) are maintained for only 2 to 3 days after administration is suspended, and follicular development may resume because of inadequate endocrine suppression.8
Patient adherence is another crucial factor when low-dose OCs are used. The risk of ovulation is at its maximum during the 7-day pill-free interval, and the risk of pregnancy increases substantially for a woman using these formulations if she does not start her new pill pack on time. In addition, individual women metabolize medications differently, and faster metabolism may jeopardize the efficacy of low-dose pills.
The Standard OC Regimen
In studies of women with premenstrual symptoms, OCs have typically been administered using a standard regimen (21/7 regimen) consisting of 21 days of estrogen-plus-progestin pills, followed by 7 pill-free days (in some regimens, placebo pills may be taken on pill-free days to increase the likelihood of timely resumption). This 21/7 regimen closely mimics a woman's average 28-day cycle—indeed, the regimen was developed with this average cycle in mind—and is also used with other contraceptive methods, such as the patch and the vaginal ring. Women who take hormonal contraceptives using this standard regimen have a monthly withdrawal bleed that traditionally has assured them that they are not pregnant.
However, the standard regimen's 7-day pill-free interval is associated with significant drawbacks. For example, commonly used low-dose OC formulations have a very real potential for reduced ovarian inhibition during this interval. Also, OC users may experience an increase in monthly hormone-withdrawal symptoms—pelvic pain, headaches, bloating, and breast tenderness—during the pill-free interval.
Hormone-related symptoms were assessed in a study of women of childbearing age who used OCs and kept daily symptom diaries.9 Women who requested OCs were recruited from an obstetrics and gynecology practice without regard to the presence of premenstrual symptoms. Of the 262 evaluable women, 193 were current OC users at study entry and 69 women were categorized as new starts because they had had no recent OC use (26 had not previously used OCs and 43 were former OC users). The various low-dose OCs used by the study participants contained 35 µg EE or less as the estrogen component plus different progestins and were administered in the standard 21/7 regimen. Participants were significantly more likely to experience hormone-withdrawal symptoms during the 7 pill-free days than during the 21 days of active hormone use. The percentage of women reporting hormone-withdrawal symptoms during the 21 days of pill use and the 7-day pill-free interval is shown in Table 1.
Women who were current OC users of more than 12 months' duration experienced headaches more commonly during the pill-free interval than during active-pill use. New-start OC users had significantly more headaches during the pill-free interval than during active-pill use in cycle 2 (71% vs 49%, P <.001) but not in cycle 1 (71% vs 62%). This increase in the incidence of headaches probably stemmed from the effect of estrogen withdrawal on the vasculature.
Current and new-start OC users both experienced significantly more pelvic pain or cramps during the pill-free interval than while taking active pills (each P <.001). In addition, current and new-start OC users both reported an increase in bloating and swelling that started during the active-pill week before the pill-free interval. For all cycles studied, current and new-start OC users both reported significantly more bloating or swelling during the pill-free interval compared with active-pill weeks (58% vs 19%, P <.0001).
In this study, breast tenderness was also more common in new-start than in current OC users. The current OC users tended to experience a greater degree of breast tenderness during the week before the pill-free interval that peaked during the pill-free interval; 16% experienced breast tenderness during active-pill weeks versus 38% during the pill-free interval (P <.001).9
Using a Shorter Pill-free Interval
Low-dose OC formulations provide a lesser degree of ovarian inhibition during the standard 7-day pill-free interval compared with higher doses.10 Shortening the pill-free interval would be logical in an attempt to maintain ovulation suppression with low-dose OC formulations. However, the first low-dose and OC formulations (35 µg EE or less) were not introduced with a recommendation for shortening the pill-free interval. Three studies conducted on the feasibility of shortening the pill-free interval are summarized in Table 2. In all of these studies, women in the groups receiving regimens with shorter pill-free intervals showed greater ovarian suppression than women who received the standard 21/7 regimen.9-11